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Why does Audition open aac file and extract aac soundtrack of video have the different length(duration) and delay? And the delay duration is 1024 samples(approximately 21 ms, 48kHz Stereo)
為何Audition CC 2018打開AAC檔案和影片中的AAC聲道會得到不同時長和延遲?且延遲是1024個Samples(約21毫秒)
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Audition doesn't open aac files, it decodes them to wav files - it has to do this, otherwise Audition couldn't play them, as they are compressed files. And as such, when they are expanded out and reconstructed there is no absolute guarantee of length. As the error is less than a single frame, it would be deemed to be acceptable (unless this was a very short file).
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Thanks for your reply.
Which one is correct? I mean the delay. aac file or video file?
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Couldn't tell without knowing precisely how long the original was. Not only that, but there's a reasonable chance that if you opened it in some other software, you'd get a slightly different result anyway, depending on how it was padded into the wav container.
Sometimes it can be quite traumatic looking at the dark underbelly of compressed files, and what they get up to!